talk

Once communication is established, the two parties can type simultaneously, with their output displayed in separate regions of the screen. Characters shall be processed as follows: Typing the erase and kill characters shall affect the sender's terminal in the manner described by the termios interface in XBD General Terminal Interface . Typing the interrupt or end-of-file characters shall terminate the local talk utility. Once the talk session has been terminated on one side, the other side of the talk session shall be notified that the talk session has been terminated and shall be able to do nothing except exit. Typing characters from LC CTYPE classifications print or space shall cause those characters to be sent to the recipient's terminal. When and only when the stty iexten local mode is enabled, the existence and processing of additional special control characters and multi-byte or single-byte functions shall be implementation-defined. Typing other non-printable characters shall cause implementation-defined sequences of printable characters to be sent to the recipient's terminal. Certain block-mode terminals do not have all the capabilities necessary to support the simultaneous exchange of messages required for talk . When this type of exchange cannot be supported on such terminals, the implementation may support an exchange with reduced levels of simultaneous interaction or it may report an error describing the terminal-related deficiency. The recipient of the talk session. One form of address is the , as returned by the who utility. Other address formats and how they are handled are unspecified. Provide a default value for the internationalization variables that are unset or null. (See XBD Internationalization Variables for the precedence of internationalization variables used to determine the values of locale categories.) If set to a non-empty string value, override the values of all the other internationalization variables. Determine the locale for the interpretation of sequences of bytes of text data as characters (for example, single-byte as opposed to multi-byte characters in arguments and input files). If the recipient's locale does not use an LC CTYPE equivalent to the sender's, the results are undefined. Determine the locale that should be used to affect the format and contents of diagnostic messages written to standard error and informative messages written to standard output. [XSI) ] ![[Option Start]]( Determine the location of message catalogs for the processing of LC MESSAGES. ![[Option End]]( When the talk utility receives a SIGINT signal, the utility shall terminate and exit with a zero status. It shall take the standard action for all other signals. If standard output is a terminal, characters copied from the recipient's standard input may be written to standard output. Standard output also may be used for diagnostic messages. If standard output is not a terminal, talk shall exit with a non-zero status. Because the handling of non-printable, non- characters is tied to the stty description of iexten , implementation extensions within the terminal driver can be accessed. For example, some implementations provide line editing functions with certain control character sequences. The write utility was included in this volume of POSIX.1-2017 since it can be implemented on all terminal types. The talk utility, which cannot be implemented on certain terminals, was considered to be a "better" communications interface. Both of these programs are in widespread use on historical implementations. Therefore, both utilities have been specified. Historical BSD and System V versions of talk terminate both of the conversations when either user breaks out of the session. This can lead to adverse consequences if a user unwittingly continues to enter text that is interpreted by the shell when the other terminates the session. Therefore, the version of talk specified by this volume of POSIX.1-2017 requires both u